Welder



Feb. 8, 1944. w, MARTIN 2,341,459

WELDER Filed Feb. 19, 1940 'atented Feb. 8, 1944 7 wnmaa William H. Martin, Pleasant Ridge, Mich; assignor to Progressive Welder Company, a corporation of Michigan Application February 19, 1940, Serial No. 319,589

2 Claims.

My invention has for its object to provide a means for insuring a high, electric contact pressure of an electric conductor against a movable, electrode-supporting member to reduce the contact resistance to the flow of a current, when directed to the electrode.

The invention provides a pressure means, which may be operated by fluid, under pressure, and lo- :ated at the pivot point of the electrical connections for producing, pneumatically, a high, electric contact pressure after the electrodes have been, manually. placed in position, with reference to an object through which the current is to be directed.

The invention may be utilized in connection with electrically-operated and manually-manipulated devices of different forms, and, to illustrate a practical application of the invention, I have selected a welder as an example of the various structures containing the invention and shall describe the selected structure hereinafter. The particular structure selected is shown in the accompanying drawing.

Fig. 1 of the drawing illustrates a side view of a welder. Fig. 2 illustrates a view of a section taken on the plane of the line 2-2, indicated in Fig. 1.

In the form of welder shown in the figures, a pair of electrodes it and II are mounted on the ends of the arms I! and i4 for engaging opposite sides of the work to produce a weld. The welder is provided with a cylinder II, which is mounted on an extension ll of the arm H, for relatively manipulating the arm l2, to cause the electrodes l and Ii to press against the work. The piston of the cylinder I5 is connected, by means of a link II, to a projection ll of the arm II. The arm I2 is pivotally connected to the arm M, by the piston rod 28, which is located in a sleeve 2| and washers 22 of insulating material to prevent conduction at the point of connection of the arms. The arm i2 has a bifurcated extension, having ears 24, and the arm I4 is provided with a web 25, located between the ears of the arm i2. The terminals 21 of the electric conductors are provided with bosses 28, which extend into the cars 24 of the bifurcated extension of the arm I2. One of the bosses 28 extends through one of the ears 24 and, electrically, contacts with the web of the arm 14, while the other terminal 21 shoulders against the other ear 24 of the arm l2, whereby the current from the conductors 30 flows through the arms I! and 14, the electrodes l0 and H, and the work 29. Except where the terminals 2'! contact with the parts of the arms i2 and I4, the terminals are insulated by the sleeves ll and the washers 32, to prevent short-circuiting of the welding current.

One end of the piston rod 20 is threaded and provided with clamping nuts 34, while the other end of the piston rod is secured to a piston 31, which is located in the cylinder 35, by the nut 34. The nuts 34 may be adJustably secured on the piston rod to produce a desired looseness of the joint to enable ready manipulation of the arm in locating the electrodes in proper positions on the work and yet to tightly clamp the parts of the joint when the air, under pressure, is directed to the cylinder A pipe 38 extends to the cylinders II and 35. The pipe 38 may be connected, by a valve 4|, to a source of supply of air pressure, through a pipe 4|. The valve is electromagnetically operated, by means of a solenoid 42, when the switch 44 is closed, to connect the solenoid 42 with a source of supply of electric current. The pressure, which is, thus, transmitted to the cylinders II and & causes the arms l2 and I4 to engage oppos sides of the work, by reason of the fact that the arms l2 and I4 are free to move, and, upon engagement of the electrodes with the work, the pressure builds up in the cylinder II, and is transmitted to the cylinder 25, which causes the plane surfaces of the arm i2 and I4 to be clamped against the plane contacting surfaces of the terminals and reduce the resistance to the flow of the welding current from the conductor: 30. to the electrodes II and l I, and through the work.

This enables, by reason of the free pivotal movement of the arms, ready placement of the electrodes in position, with reference to the work. When the electrodes have been placed in position by the operator, and the cylinders connected to the source of air, under pressure, the resistance to flow of the current, to the electrodes, is greatly reduced by the operation of the cylinder SI, which tightly clamps the plane contacting surfaces of 'the terminals and the arms together.

I claim:

1. Welding apparatus comprising, a frame,

welding electrodes mounted on said frame, means 4 for actuating said electrodes between work-engaging and released positions, means including a pair of conductors for completing an electric circuit to said electrodes, means for pivotally mounting said frame relative to at least one of said conductors, with conductive surfaces on said frame and said one. conductor in engagement with each other, means constructed and ar- 2. The structure orclaiml wherein said Irame comprises a pair ofntvotally connected arms each of which carries one of said. electrodes. and

wherein the pivotal axis or said armsisooincident with the pivotal axis between said i'rame and said'one conductor.

WILLIAM H. MARTIN. 

